Wellbore stability analysis acts an important role in the drilling design to avoid pipe-stuck, lost circulation and the other instability-induced problems. However, the conventional linear elastic model used by the industry is too conservative in predicting the mud weight window. This project is aimed at improving the accuracy of wellbore stability analysis. An elastoplastic model with Drucker-Prager yield criterion featured by strain hardening is proposed to characterize the rock behavior. Object-oriented finite element analysis simulator, NSMOOM, is programmed in MATLAB. The simulator is verified with the analytical solution in the elastic domain and with the commercial software ABAQUS in the elastoplastic domain. Upon the good verification results, the code is applied to an under-balanced-drilling case. For the case study, a good match is shown between the prediction of the proposed elastoplastic model and the actual wellbore response. On the other hand, no available mud weight window for under-balanced-drilling can be calculated by the pure elastic model. In conclusion, the proposed model provides a more realistic tool to predict wellbore stability.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-05162016-095915 |
| Date | 29 July 2016 |
| Creators | Huang, Chang |
| Contributors | Tyagi, Mayank, Akbari, Babak, Chen, Shengli |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-05162016-095915/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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